fix: always display thumbs, even with zero reactions

src/rural_dict/templates/index.html

@@ -39,7 +39,7 @@
         <p><i>{{ example|safe }}</i></p>
       </div>
       <div>{{ contributor|safe }}</div>
-      {% if thumbs_up and thumbs_down %}
+      {% if thumbs_up is not none and thumbs_down is not none %}
       <p>
         <span title="thumbs up">👍{{ thumbs_up|safe }}</span>
         <span title="thumbs down">👎{{ thumbs_down|safe }}</span>